The invention relates to a device for the recognition of caries, plaque or bacterial infection of teeth.
Such a device is known for example from DE 30 31 249 C2. There, a tooth to be investigated is irradiated with a virtually monochromatic light source, whereby a fluorescence radiation is excited at the irradiated tooth. The fluorescence radiation thus excited at the tooth is acquired and evaluated, whereby in the fluorescence radiation clear differences appear as between carious and healthy tooth regions. Thus, in the red spectral region of the fluorescence spectrum of the tooth (ca. 550 to 650 nm) the intensity is significantly higher than with a healthy tooth. Thus, on the basis of the acquisition of the fluorescence radiation of the investigated tooth, a healthy tooth region can be unambiguously distinguished from a carious tooth region in a contactless manner.
A similar device for the recognition of caries is described in DE 42 00 741 A1, it being further proposed in this document to excite the fluorescence of the tooth by means of an excitation radiation having a wavelength in the range 360 to 580 nm and to filter out the thus obtained fluorescence radiation of the tooth for wavelengths from 620 nm. By means of these measures, the separation between the wavelength of the excitation radiation and the received fluorescence radiation is sufficiently large that the excitation radiation does not corrupt the evaluation results by superimposition on the fluorescence radiation.
Also from DE-U1-93 17 984 there is known a device for the recognition of caries whereby the excitation radiation is generated not continuously but pulsed, in an excitation interval. The fluorescence radiation of the investigated tooth brought about at the tooth due to the excitation radiation is acquired during an evaluation interval time-delayed with respect to the excitation interval.
From the above documents it is known only to irradiate a tooth to be investigated with a single light conductor and to detect the fluorescence radiation from the irradiated tooth by means of a detection light conductor arranged next to the emission light conductor. Thereby, however, non-homogeneous irradiation of the tooth to be investigated can occur and because of the arrangement of the detection light conductor next to the emission light conductor the fluorescence radiation is not precisely acquired.